MODOT BINDER IGNITION OVEN TRAINING/CERTIFICATION COURSE

Missouri University of Science & Technology Department of Civil, Architectural, and Environmental Engineering

1-21-11 4-14-11 Revision 4-27-12 Revision 12-18-13 Revision 4-22-15 Revision

Time 8:00-8:15

BINDER IGNITION OVEN CERTIFICATION COURSE 2014-2015 Module Location Topic Intro Lecture Intro/welcome

8:15-9:30 9:30-10:30 10:30-10:50

Lecture Lecture Lab

10:50-11:00 2 hours ?-Until all have finished

Lecture Lecture Lab

BI Oven Schedule 14-15.doc

Binder Ignition Oven Homework Binder Ignition test demo Hands-on practice Course Review Written Exam Proficiency Exam

Instructor Richardson Richardson Richardson Lusher Staff Richardson Richardson Staff

AASHTO T308 Determining the Asphalt Binder Content of Hot Mix Asphalt (HMA) by the Ignition Oven Method

MODOT BINDER IGNITION OVEN TRAINING/CERTIFICATION COURSE

Missouri University of Science & Technology Department of Civil, Architectural, and Environmental Engineering

1-21-11 4-14-11 Revision 4-27-12 Revision 12-18-13 Revision 4-22-15 Revision

AASHTO T308 Determining the Asphalt Binder Content of Hot Mix Asphalt (HMA) by the Ignition Oven Method

SCOPE „

Background

„

Binder Content Role in QC/QA Sampling Test procedure Field verification

„ „ „

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BINDER CONTENTWHY TEST? „

Excessive binder can cause instability e.g. rutting, shoving, corrugations, bleeding

„

Binder content is an important part of the dustto-binder ratio which affects compactibility and cohesion

4

BINDER CONTENTWHY TEST? „

Insufficient binder can lead to lack of adhesion, raveling, stripping, and cracking

5

AASHTO TEST METHODS & SPECIFICATIONS „ „ „ „ „

T168 Sampling Hot Mix R 47 HMA Sample Splitting T329 Moisture Content of Hot Mix T 308 Binder Content Ignition Oven T30 Sieve Analysis of Residue

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Equipment „ „ „ „ „

Ignition Furnace Basket assembly Oven (110 ± 5 C) Balance Safety Equipment: face shield, gloves, long-sleeved jacket, protective basket cage

7

BINDER CONTENT TEST METHODS „ „

Solvent extraction T 164 Nuclear gage: T 287, TM 54 „ „

„

Low radiation Regular radiation

Ignition oven: T 308 „

Method A „ Convection oven „ Infrared oven

„ Method

„ „

B

Method A: internal scale Method B: no internal scale

8

SOLVENT EXTRACTION T 164 „ „ „

Solvent health issues Solvent disposal issues Thus, expensive

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NUCLEAR GAGE T 287, TM 54 „ „ „

Health issues Interferences Calibration issues

10

IGNITION OVEN T 308 Method A: „ more

convenient, higher lab production rates

11

METHOD “A”

„ Convection

„ Infrared

oven (NCAT)

oven:

„First

generation „Second generation (NTO)

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HEAT TRANSFER „

Convection: heat warms the air, which warms the sample

„

Infrared: electromagn etic energy waves directly heat the sample 13

14

Convection Infrared

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BASKETS

16

CONVECTION OVEN BASKET

17

INFRARED OVEN

Default Normal Option 1 Less Option 2 More

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6

SECOND GENERATION INFRARED

19

IGNITION OVEN Method B: no internal scale „ lower

oven cost; less operational problems

20

METHOD “B” „

Note the special heat resistant shirt

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TYPES OF METHODS In Missouri „ „ „ „ „

NCAT oven - vast majority Nuclear – a few Low radiation nuclear - 1 First generation infrared ignition oven – 1 Second generation infrared ignition oven – 1

22

REPORTED USAGE „

Dolomite: „ „

„

Nuclear Low radiation nuclear

All other: convection or infrared ignition ovens

23

SCOPE „

Background

„

Binder Content Role in QC/QA

„

Sampling Test procedure Field verification

„ „

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Binder Content Role „

Mix design & acceptance

„

Field Verification of mix

25

Mix Design & Mix Acceptance „

„

Contractor designs mix & submits target binder content to MoDOT MoDOT approves and sets JMF target binder %

26

Binder Content Role „

Mix design & acceptance

„

Field verification of mix

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CONTENT „

Binder content of mix

„

Binder content of RAP Aggregate gradation

„

28

% BINDER Design (target) binder content is determined during mix design and verified/approved by MoDOT „ May have to be adjusted in the field resulting in a new target binder content „

29

Binder Role „

Binder content is a pay factor in 403 projects

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Location of Target Binder Content on JMF

31

SCOPE

„

Background Binder Content Role in QC/QA

„

Sampling

„

Test procedure Field verification

„

„

32

Binder Content Samples „ „

401: plant 403: roadway

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Location of Target Binder Content on JMF

31

Binder Content Field Verification „ „

401: JMF ± 0.3% 403: JMF ± 0.3%

34

LOOSE MIX: 403 Volumetric/%Binder Sample „

Sampling Frequency: QC: one per sublot QA: one per lot *“independent sample” „ QA: once per day *test QC “retained sample”. This may be omitted on days when independent QA sample is taken, if confident and “favorable comparison” exists between QA and QC* * Per EPG and Task Force „ „

35

Loose Mix: 401 „

„

„

QC: 1000 tons or a minimum of once per day when production exceeds 1000 tons per day. If less than 1000 tons per day, test at least once; RE may waive testing if less than 200 tons per day QA: one independent sample per day when production exceeds 500 tons per day QA: Retained QC sample split: once per 5 days

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403: SAMPLE „

50 lb. sample –get 2 portions for the 2 volumetric pucks plus Rice Rice Gyro

Gyro

37

403 REMIX, QUARTER AGAIN

Ignition Oven & Moisture

Ignition oven & Moisture

38

Or REMIX, QUARTER AGAIN Nuclear & Moisture

Nuclear and Moisture

Nuclear and Moisture

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IGNITION OVEN SPECIMEN SIZE Mix

NMS Specimen in. Size g SP048 & BP-3 #4 1200-1700 SP095 3/8 1200-1700 SP125 & BP-1 & 1/2 1500-2000 BP-2 SP190 & 3/4 2000-2500 Bit Base SP 250 1 3000-3500

40

IGNITION OVEN SPECIMEN SIZE „

Large specimens of fine mixes tend to result in incomplete ignition

41

SCOPE

„

Background Binder Content Role in QC/QA Sampling

„

Test procedure

„

Field verification

„ „

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TEST PROCEDURE „ „

Corrections Binder content test procedure

43

IGNITION OVEN BASICS „%

Binder: loss in mass of specimen „ Problem: other materials also burn off „ moisture „ aggregate

44

TEST PROCEDURE „

Corrections

„

Binder content test procedure

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BINDER CONTENT CORRECTIONS „

Moisture

„

Aggregate burn loss Temperature effects on weighing

„

46

MOISTURE CORRECTION „ „ „

Moisture in mix will burn off, too. This will count as binder unless corrected Correction: Dry mix to a constant mass at 110 ± 5 C prior to testing „ “Aging”—must still verify that constant mass has been achieved Or „ Determine moisture content of mix (AASHTO T 329), subtract it from the apparent binder content „

47

AASHTO T 329-13 „ „ „ „

MoDOT is now following AASHTO T 329 Temperature now is at 325 ±25 F Initial drying time is 90 minutes Moisture is now calculated based on wet weight of HMA

MC = % moisture Mi(wet) = initial mass of mix, wet Mi(dry) = initial mass of mix, dry

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MOISTURE DATA SHEET MOISTURE CONTENT OF HOT MIX ASPHALT (HMA) by OVEN METHOD AASHTO T 329-13 (for ignition oven correction purposes) Project No.

Job No.

Route

County

Technician

Date

Sublot No.

Mix No.

Oven Temp.

Time in

Time out

Interval

Sample: Pan wt. (g)

Sample: 340

Mix + pan wt., moist (g) = (W wet)

1840

Mix + pan wt., dry (g) [Trial 1]

1839

Mix + pan wt., dry (g) [Trial 2]

1838

Mix + pan wt., dry (g) [Trial 3] = (W dry)

1838

NOTE: All weights to nearest 0.1 gram and % moisture to nearest 0.01%

49

MOISTURE TESTING FREQUENCY: Several per Day „ „ „ „ „

„

High RAP/RAS mixtures especially prone to moisture Rainy weather “Warm mix” New aggregate If plant operator reports burning more fuel to maintain temperature Fluctuating volumetrics or binder contents

50

MOISTURE TESTING FREQUENCY: Less Often „ „ „

Dry weather Same stockpiles No moisture when tested

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MOISTURE DATA SHEET MOISTURE CONTENT OF HOT MIX ASPHALT (HMA) by OVEN METHOD AASHTO T 329-13 (for ignition oven correction purposes) Project No.

Job No.

Route

County

Technician

Date

Sublot No.

Mix No.

Oven Temp.

Time in

Time out

Interval

Sample:

Sample:

Pan wt. (g)

340

Mix + pan wt., moist (g) = (Wwet)

1840

Mix + pan wt., dry (g) [Trial 1]

1839

Mix + pan wt., dry (g) [Trial 2]

1838

Mix + pan wt., dry (g) [Trial 3] = (Wdry)

1838

NOTE: All weights to nearest 0.1 gram and % moisture to nearest 0.01%

49

BINDER CONTENT CORRECTIONS „

Moisture

„

Aggregate burn loss

„

Temperature effects on weighing

52

Asphalt Binder Correction Factor (Aggregate Correction Factor) „

„

„

To correct for loss of mass during the mix ignition due to aggregate burn-off Determined during mix design and then verified by mix designer (usually QC) Re-determined if mix design changes (e.g. >5% change in stockpiled aggregate proportions)

53

Asphalt Binder Correction Factor (Aggregate Correction Factor), cont’d. „

CF Procedure: „ Mix

specimen in lab with dry aggregate at a known (actual) % binder „ Input “zero” for the CF „ Burn, obtain measured (apparent)% binder „ The difference between the measured and the actual % binder is the Asphalt Binder Correction Factor (CF ) „ If the CF is > 1.0%, redetermine at a lower 54 temperature

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Asphalt Binder Correction Factor (Aggregate Correction Factor), cont’d. „

Lab-produced sample (dry)

„

Math:

„

The difference is the aggregate mass loss The Measured content can be from the oven ticket If the CF is > 1.0%, re-determine at a lower temperature 55

„ „

CONVECTION OVEN TEMPERATURES „

AASHTO: „ Normal: „ High

„

538 C CF ’s (>1.0%): 482 C

MoDOT: „ Normal:

538 C CF ’s: if >1.0% try 482 C „ Very high CF ’s: if >1.0% at 482 C, use 427 C „ High

56

Asphalt Binder Correction Factor (Aggregate Correction Factor) Data Sheet

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Asphalt Binder Correction Factor (Aggregate Correction Factor) Data Sheet

57

INFRARED BURN PROFILES „ „ „

“Default”- most mixes “Option 1” (Less)- for Cf >1.0% eg.RAP containing dolomite “Option 2” (More) – hard to burn mixes

58

Asphalt Binder (Aggregate) Correction Factors „

„

Anecdotal: Infrared runs ~0.05% higher than convection oven AMRL Proficiency samples are comparable

59

RAP Aggregate Correction Factor (Asphalt Binder Correction Factor) „

Follow TM-77: Assumes aggregate CF for RAP is same as CF for virgin aggregate „ Follow the standard procedure as if there was no RAP, i.e., use only the virgin aggregate, and only the binder content associated with the virgin aggregate portion when fabricating the specimen „

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BINDER CONTENT CORRECTIONS „ „ „

Moisture Aggregate burn loss

Temperature effects on weighing

61

CONVECTION OVEN: TEMPERATURE COMPENSATION FACTOR „ „ „

„

Material “weighs” differently at elevated temperatures Mass loss shown on the oven printout must be corrected Oven calculates and prints the “Temperature Correction Factor (TCF)” for the particular test run

TCF = apparent loss in weight due to heating

62

USE OF TEMPERATURE CORRECTION FACTOR „

„

When determining the Aggregate Correction Factor, if the oven printout is used for determination of the Measured Asphalt Content, include the Temperature Correction Factor (TCF) If all weighing is performed outside of the oven, do not use the TCF

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Second Generation Infrared oven „ „

No Temperature Correction Factor Scale is better insulated from the chamber

64

TEST PROCEDURE „

Corrections

„

Binder content test procedure

65

REHEATING EPG 403.1.5

„

If a retained sample must be reheated: Warm the sample until workable „ Spread it in a large pan and reheat—this will minimize the damage caused by reheating „

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CONVECTION OVEN TEST PROCEDURE: Method A

„

1. Dry specimen at 110 ± 5 °C or determine moisture content (T 329-13):

„

2. Enter the chamber set point (desired oven temperature). 3. Enter the asphalt correction

„

factor (CF)

67

CONVECTION OVEN TEST PROCEDURE: Method A „

4. Weigh the test specimen.

„

5. Enter the specimen weight. 6. Place the sample in the oven and compare the weight indicated by the oven scale to that of the external scale the sample was first weighed on (this helps detect if basket is contacting the furnace wall)

„

68

CONVECTION OVEN „ „

TEST PROCEDURE: Method A 7. Burn 8. Oven will stop when burn is complete and will calculate % binder based on the: Original specimen weight entered „ Total loss „ Asphalt correction factor (CF ) that you entered. „ “Temperature Compensation” factor that the oven calculates = apparent loss in weight due to heating. „

„

4/22/15

9. You must then correct (subtract) for moisture if started with a wet sample 69

23

Test Results Printout

70

ASPHALT CONTENT IGNITION METHOD (AASHTO T 308-10) METHOD A

Reproducing Oven Ticket Values Project No.

Job No.

Route

County

Technician

Date

Sublot No.

Mix No.

Empty Basket Assembly Weight (g), [Te]

3000

Basket Assembly + Wet Sample Weight (g), [Ti]

4270

Wet Sample Weight (g), [W i = (Ti - Te)]

1270

Loss in Weight (g), [L] (from tape)

79.8

Total % Loss, [PL= (L / W i) x100] Temperature Compensation (%), [Ctc] (from tape) % AC, uncorrected, [Pbu = PL - Ctc] Aggregate Correction (Calibration) Factor (%), [Cf] (from tape) Calibrated %AC (from ignition oven tape), [Pbcal = Pbu – Cf] % Moisture Content, [MC] (previous test) % AC, corrected (by weight of mix), [Pb = Pbcal – MC]

6.28 -0.17 6.11 -0.26 5.85 -0.10

71 5.75

Asphalt Binder Correction Factor (Aggregate Correction Factor) Calculation If final weighing is performed on bench top scale, calculation:

Where: Mi(wet) = initial mass of mix, wet = final mass of mix Mf MC = % moisture Cf = Asphalt Binder Correction Factor (old Aggregate Correction Factor) 72

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Test Results Printout

70

ASPHALT CONTENT IGNITION METHOD (AASHTO T 308-10) METHOD A

Reproducing Oven Ticket Values Project No.

Job No.

Route

County

Technician

Date

Sublot No.

Mix No.

Empty Basket Assembly Weight (g), [Te]

3000

Basket Assembly + Wet Sample Weight (g), [Ti]

4270

Wet Sample Weight (g), [Wi = (Ti - Te)]

1270

Loss in Weight (g), [L] (from tape)

79.8

Total % Loss, [PL= (L / Wi) x100]

6.28

Temperature Compensation (%), [Ctc] (from tape) % AC, uncorrected, [Pbu = PL - Ctc] Aggregate Correction (Calibration) Factor (%), [Cf] (from tape) Calibrated %AC (from ignition oven tape), [Pbcal = Pbu – Cf] % Moisture Content, [MC] (previous test) % AC, corrected (by weight of mix), [Pb = Pbcal – MC]

-0.17 6.11 -0.26 5.85 -0.10

71 5.75

Example Manual Method „ „ „ „

Moisture = 0.05% Cf = 0.22% Initial wet mass = 5400 g Final burned mass = 5256 g

73

ASPHALT CONTENT IGNITION METHOD (AASHTO T 308-10) METHOD A Manual Weighing Method Project No.

Job No.

Route

County

Technician

Date

Sublot No.

Mix No.

Empty Basket Assembly Weight (g), [Te]

3000

Initial Basket Assembly + Wet Sample Weight (g), [Ti]

5400

Initial Wet Sample Weight (g), [W i = (Ti - Te)]

2400

Final Basket Assembly + Sample Weight (g), [Tf]

5256

Loss in Weight (g), [L= Ti - Tf]

144

% Loss, [PL= (L / W i) x100]

6.00

Aggregate Correction (Calibration) Factor (%), [Cf]

-0.22

Calibrated %AC, [Pbcal = PL – Cf]

5.78

% Moisture Content, [MC] % AC, corrected (by weight of mix), [Pb = Pbcal – MC]

-0.05

74

5.73

TEST PROCEDURE Method B „ „ „ „ „ „

„

1. Weigh out specimen. 2. Burn for about 45 minutes. 3. Remove, cool, weigh. 4. Burn for another 15 minutes. 5. Remove, cool, weigh. 6. Keep repeating until 2 consecutive mass weighings do not change by > 0.05%. 7. Subtract moisture %. 75

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ASPHALT CONTENT IGNITION METHOD (AASHTO T 308-10) METHOD A Manual Weighing Method Project No.

Job No.

Route

County

Technician

Date

Sublot No.

Mix No.

Empty Basket Assembly Weight (g), [Te]

3000

Initial Basket Assembly + Wet Sample Weight (g), [Ti]

5400

Initial Wet Sample Weight (g), [Wi = (Ti - Te)]

2400

Final Basket Assembly + Sample Weight (g), [Tf]

5256

Loss in Weight (g), [L= Ti - Tf]

144

% Loss, [PL= (L / Wi) x100]

6.00

Aggregate Correction (Calibration) Factor (%), [Cf]

-0.22

Calibrated %AC, [Pbcal = PL – Cf]

5.78

% Moisture Content, [MC] % AC, corrected (by weight of mix), [Pb = Pbcal – MC]

-0.05

74

5.73

OVEN VERIFICATION „

The oven must be “verified’ after a move—the balance needs to be checked

76

Common Testing Errors/Source of NonComparison/Early Shut-off „

„

„ „

Starting test when oven is cold: incomplete burn; can affect TCF Neglecting to push “Start” (binder burns but is not recorded) Not cleaning oven & vents often enough Using vent pipe less than 4 in, diameter (NTO clogs more quickly) 77

Common Testing Errors/Source of NonComparison/Early Shut-off Asphalt correction factor (CF) not used „ Not cleaning baskets „ Allowing scale plate or support tubes to rub „ Not spreading specimen out „ Not tearing off ticket before opening oven door „ Allowing door to not latch correctly „ Not correcting for moisture (e.g. when plant speed increases, etc) „

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Common Testing Errors/Source of NonComparison/Early Shut-off „ „

„

„

Using an oversize specimen Not using the same size specimen for asphalt correction factor (CF) determination and all production tests Using a plant-made specimen instead of a lab-made specimen for (CF) determination Not double-checking specimen weight on oven scale against exterior scale weight 79

Common Testing Errors/Source of NonComparison/Early Shut-off Materials used for (CF) determination not the same as project materials „ Inaccurate asphalt contents used for (CF) determination „ QA & QC starting with different temperature specimens „ Door left open too long between loadings „

80

Common Testing Errors/Source of NonComparison/Early Shut-off „

„ „

QA & QC starting with different temperature specimens Wrong chamber set point Wrong burn profile

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OPERATIONAL PROBLEMS „

Oven won’t shut itself off— it’s OK to manually shut off as long as 3 consecutive readings show less than 0.01% loss and the sample appears to be completely burned (EPG 403.1.5)

82

Premature Burn Stop „ „ „ „

Vibrations Basket or strap up against wall or top of chamber Clogged port Used U.S. date, not European date (1998-2000 NCAT models)

83

NTO Incomplete Burn Pattern: Shingle Mix

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Soot

85

Coke

86

SCOPE

„

Background Binder Content Role in QC/QA Sampling Test procedure

„

Field verification

„ „ „

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MoDOT SPREADSHEET

88

89

Binder Portion

90

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MoDOT SPREADSHEET

88

89

Binder Portion

90

MODULE CONTENT „

Binder content of mix

„

Binder content of RAP

„

Aggregate gradation

91

RAP Binder Content „ „ „ „ „

Per Spec 403.2.6, RAP binder content must be determined QC: 1 per lot QA: 1 per project T164 (solvent extraction) Can use T308 (ignition) if a correction factor is determined which is the difference between T164 & T308 (best to use your own oven when T164 is determined by another lab) 92

RAP & RAS „

„

„ „

4/22/15

Some contractors stockpile RAP & RAS, prepare (grind) it, and sample it. Send sample to a commercial lab to have extractions run (T164), obtain binder content & gradation This is what is submitted to MoDOT during mix design During production, RAP is sampled and ignition oven used to get binder content & gradation 93

31

MODULE CONTENT

„

Binder content of mix Binder content of RAP

„

Aggregate gradation

„

94

GRADATION SAMPLES „

„

„

MoDOT allows gradation sample testing to be satisfied by using the residue from the HMA ignition oven sample. An aggregate (gradation) correction factor (AGCF) may be necessary to account for the breakdown in rock. RAP gradation in the field is determined with ignition oven 95

RAS Gradation „ „ „

Not recommended to use T308 on RAS (too dangerous) Fan will suck fines out Use extraction to get gradation or use the standard gradation

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GRADATION SAMPLES „

„ „

When determining the aggregate (gradation) correction factor (AGCF), prepare a aggregate blank (no binder) specimen. Do a washed gradation analysis (T 30) Do a washed gradation analysis of the burned HMA specimen (T 30)

97

GRADATION SAMPLES Plus #200 Portion „

„

„ „ „

Determine a difference for each sieve. Calculate the average difference. If the difference on any sieve exceeds the allowable, then each sieve must have the AGCF applied. Allowable differences:  #8: ± 5.0%  #200 to < #8: ± 3.0%

98

GRADATION SAMPLES Minus #200 Portion „

Calculate the difference between the burned %-#200 and the blank (unburned) % #200:

„

(%-#200)burned- (%-#200)blank

„

If difference is ›0.5%, use the difference as the AGCF for the minus #200 material.

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Conventional vs. Infrared Conventional (NCAT) Chamber temperature 240 v

Infrared (NTO) Burn profile 120 or 240 v

Ceramic filter or afterburner

none

Reports burn time to the nearest minute

Reports burn time to the nearest second (thus is not an indication of operator interference) No asterisk

Asterisk at end of machine stop

100

Conventional vs. Infrared Conventional (NCAT) Infrared (NTO) Fan starts when “Start” is pressed

Fan does not start when “Start” is pressed: good for RAP/RAS- won’t suck out fines; Bad: odors Reduced emissions, but still requires venting Requires cleaning more often No Temperature Compensation Factor

101

SUMMARY „

„ „ „ „

„ „

„

1. Sample loose mix every sublot (QC) or every day (QA). 2. Obtain specimen from quartered sample. 3. Specimen size is tied to NMS of gradation. 4. Burn 5. Loss of mass is the total of burned off binder, water, & aggregate. 6. Subtract the loss of aggregate & moisture. 7. Remains of the HMA burned specimen may be used for checking gradation. RAP binder content required 102

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ASPHALT CONTENT IGNITION METHOD (AASHTO T 308-10) METHOD A Asphalt Binder Correction Factor (CF) Determination (a.k.a. aggregate correction factor) 1.

Run a butter mix through the mixing equipment.

2.

For a given mix, prepare two asphalt binder correction factor (CF) specimens at the design asphalt content using oven dry aggregate. It is recommended that the CF and field verification specimen sizes be the same.

3.

Obtain the tare weight of the baskets, pan, and lid.

4.

Place the hot mix into the sample basket. If the mix has cooled, warm it at 110 ± 5°C prior to placing in the basket. Spread the mix in the basket, being careful to keep the mix away from the sides. Allow at least ¾” clearance.

5.

Test (burn) the specimens as discussed in “Test Procedure.”

6.

If the difference between the measured binder contents of the two replicate specimens is more than 0.15%, test two more specimens. Discard the high and low values.

7.

Calculate the CF by determining the difference between the actual and measured asphalt binder contents [Actual %AC – Measured %AC] for each sample, and averaging the two differences. The “Actual %AC” is the amount weighed out in the batching process, expressed as a percent by weight of the mix.

8.

If the CF exceeds 1.0%, MoDOT Standard Specification Section 403.19.3.1.1 modifies AASHTO T 308-10 in the following manner: A. According to AASHTO T 308-10, if the CF exceeds 1.0% at the typical chamber temperature of 538°C (1000°F), lower the chamber temperature to 482 ± 5°C (900 ± 8°F). If the CF determined at this lower temperature is less than or equal to 1.0%, use that CF for subsequent testing on that particular mix. B. However, according to MoDOT Standard Specification Section 403.19.3.1.1, if the CF determined at 482 ± 5°C (900 ± 8°F) exceeds 1.0%, lower the chamber temperature to 427 ± 5°C (800 ± 8°F). Use the CF obtained at 427°C even if it exceeds 1.0%.

Ignition Oven Test (4-22-15).doc

ASPHALT CONTENT IGNITION METHOD (AASHTO T 308-10) METHOD A Asphalt Binder Correction Factor (CF) Determination Sample_____________________Lab No.________Date______Initials______ Replicate

1

2

3

4

Test Temperature Tare (basket, etc.) Mass (g) Total Dry Mass (g) Initial Dry Specimen Mass (g) Loss in Weight (g) %AC, measured = M %AC, actual = A %ACdiff (M1 – M2) CF = M – A CF, average

Ignition Oven Test (4-22-15).doc

> 0.15%? If so, 2 more replicates

ASPHALT CONTENT IGNITION METHOD (AASHTO T 308-10) METHOD A Specimen size: Use the following table. It is recommended that the field verification specimen size be the same as the correction factor specimen size. NMS (mm)

Sieve Size

Minimum Specimen Size* (g)

4.75

#4

1200

9.5

3/8”

1200

12.5

1/2”

1500

19.0

3/4"

2000

25.0

1”

3000

37.5

1 ½”

4000

*Specimen sizes shall not be more than 500g greater than the minimum. POSSIBLE SETTING CHANGES 1.

2.

To change the Stability Threshold: A.

With oven off, press the “Calibration Factor” key while simultaneously pressing the Power Switch “on.”

B.

Enter new Stability Threshold value. Observe the Percent Loss window for the new value. Maximum allowable = 0.02.

C.

Press the Power Switch “off” then “on” to return oven to normal operation.

To change filter (afterburner) temperature (750°C typically): A.

Press #5 key while simultaneously pressing the Power Switch “on.”

B.

Enter new temperature.

C.

Press “Enter.”

D.

New setpoint will be displayed.

Ignition Oven Test (4-22-15).doc

MAINTENANCE 1. To check to see if the venting system is clogged, use the “Lift Test” procedure while the oven is at room temperature. With the power on, initiate a test (push “Start” button) without anything in the oven chamber. The blower fan will turn on. Watch the balance display. The display should read between -4 and -6 grams if the venting is adequate. 2.

Burn accumulated soot out of the chamber by running the testing procedure at an elevated temperature without a sample.

TEST PROCEDURE 1. To change setpoint (furnace) temperature (538°C is typical):

2.

A.

Press “Temp”

B.

Enter new setpoint

C.

Press “Enter”

D.

Press “Temp” again to verify new setpoint

To change the Asphalt Binder Correction Factor (CF): A.

Press “Calib. Factor”

B.

Enter new CF

C.

Press “Enter”

D.

Press “Calib. Factor” again to verify

3.

Preheat the oven to the setpoint, typically 538°C.

4.

If the moisture content will not be determined, oven-dry the specimen at 110 ± 5°C to a constant mass.

5.

Weigh the empty basket, etc. on an external scale to the nearest gram.

6.

Place half the sample in the bottom basket and the other half in the top. Keep the specimen at least ¾” away from the basket sides. For larger samples, some operators make a hole in the middle of the mix.

7.

Weigh the loaded assembly. Calculate the mass of the specimen.

8.

Press the “Weight” key and enter the specimen mass. Press “Enter.”

Ignition Oven Test (4-22-15).doc

9.

Press the “Weight” key again to verify specimen mass entry.

10.

Press the “0” (zero) key to tare the internal balance.

11.

Don your clean gloves, safety face shield, and safety attire.

12.

Carefully load the specimen into the oven by inserting the basket until the handle tines touch the back of the oven. Make sure the basket is centered and is not touching the walls. Shut the door.

13.

Observe the internal scale reading. The displayed value should check with the external scale value of basket assembly + dry specimen within ± 5 grams.

14.

Press the “Start/Stop” key to initiate the ignition procedure.

15.

When weight loss stabilizes (the change in %AC readings will not exceed 0.01% for three consecutive minutes), the oven will automatically end the test and print out the results. Depending on the oven setup, an alarm may sound and one may have to press the “Start/Stop” key to unlock the door.

16.

Remove the printed results before opening the door as the tape is heatsensitive.

17.

Again don the safety gear, open the door, and remove the basket and mount it on the cooling plate. Cover with the cooling cage.

18.

Determine and record the final mass of the specimen, Mf.

19.

From the total % loss, the oven will automatically subtract the CF and the Temperature Compensation to give the %AC (by weight of mix). The %AC by weight of aggregate is the “Bitumen Ratio.”

20.

Check for unburned asphalt (coke). If present, start with a new specimen. NOTE: Read the manufacturer’s manual for additional information on safety and more detailed instructions on maintenance and operation.

Ignition Oven Test (4-22-15).doc

ASPHALT CONTENT IGNITION METHOD (AASHTO T 308-10) METHOD A Manual Weighing Method Project No.

Job No.

Route

County

Technician

Date

Sublot No.

Mix No.

Empty Basket Assembly Weight (g), [Te] Initial Basket Assembly + Wet Sample Weight (g), [Ti] Final Basket Assembly + Sample Weight (g), [Tf] Loss in Weight (g), [L= Ti - Tf] % Loss, [PL= (L / W i) x100] Aggregate Correction (Calibration) Factor (%), [Cf] “Calibrated %AC”, [Pbcal = PL – Cf] % Moisture Content, [MC] % AC, corrected (by weight of mix), [Pb = Pbcal – MC]

Ignition Ovens Forms.doc (11-24-06;12-28-06;12-12-08;3-9-10;12-14-10;4-14-11; 12-18-13; 4-22-15)

Ignition Oven Test (4-22-15).doc